1. Field of the Invention
The present disclosure relates generally to data networks.
2. Description of the Background Art
A network switch is a device that provides a switching function (i.e., determines a physical path) in a data communications network. Switching involves transferring information, such as digital data packets or frames, among entities of the network. Typically, a switch is an intelligent processor having a plurality of network port cards or ports coupled to a backplane. In the switching art, the network port cards are typically called “blades.” The blades are interconnected by a “switch fabric.” Each blade includes a number of physical ports that couple the switch to the other network entities over various types of media, such as Ethernet, FDDI (Fiber Distributed Data Interface), or token ring connections. A network entity includes any device that transmits and/or receives data packets over such media.
The switching function provided by the switch typically includes receiving data at a source port from a network entity and transferring the data to a destination port. The source and destination ports may be located on the same or different blades. In the case of “local” switching, the source and destination ports are on the same blade. Otherwise, the source and destination ports are on different blades and switching requires that the data be transferred through the switch fabric from the source blade to the destination blade. In the case of a multicast data transfer, the data may be provided to a plurality of destination ports of the switch.
It is desirable to improve apparatus and methods for network switching.